Ducks often molt just before they migrate. Some species of duck undergo long migrations.

During breeding season, male ducks are often more brightly colored than females of the same species.

Sexual dimorphism is the condition in which males and females of the same species share physical differences other than differences in their sexual organs.

Outside of breeding season, the plumage of male ducks becomes duller and more closely resembles the plumage of females.

When male birds develop duller coloring outside of breeding season, so that they look like females, the males are said to be wearing eclipse plumage.

A duck’s diet can include grass, water plants, insects, worms, fish, frogs and small mollusks.

Ducks have broad, flat beaks, or bills.

They can use their bills to tear up grasses and to dredge worms and small mollusks out of mud.

Ducks have comb-like structure on the sides of their bills, which they use to strain water while food remains trapped inside and to preen (groom) themselves.

A duck’s bill, like the bills of other anseriformes, contains plates known as lamellae. Ducks use these lamellae to filter food particles from the water.

Ducks are usually monogamous.

Humans often hunt wild ducks for food or for sport.

Many duck species have been domesticated for their meat, their eggs and their feathers.

The down of ducks is particularly valuable.

Down is a layer of fine feathers that lies under the outer feathers of birds. It can provides excellent insulation.

When birds are very young, they are covered in down. They grow feathers as they get older.

Ducks were first domesticated thousands of years ago.

Some people keep ducks as pets.

A female duck is called a hen. A male duck is a drake. Young ducks are known as ducklings.